MULTIPHOTON RESONANCE WITH ONE TO MANY CYCLES

Using radio frequency pulses we connect the relatively unstructured response of a two level system to a half cycle pulse to the resonant response to a monochromatic wave. There is an obvious change from the nonresonant effect of a half cycle pulse to an interference pattern analogous to a Young{close_quote}s two slit interference pattern with two cycles. The analog of illuminating more slits, adding progressively more cycles, leads to a gradual evolution of the interference maxima into sharp resonances. The structured response to {ital M} cycles is implicit in the response to one cycle. {copyright} {ital 1996 The American Physical Society.}